Many people use mobile stations, such as cell phones and personal digital assistants, to communicate with cellular wireless networks, which typically provide communication services such as voice, text messaging, and packet-data communication. These mobile stations and networks typically communicate with each other over a radio frequency (RF) air interface according to a wireless protocol such as Code Division Multiple Access (CDMA), perhaps in conformance with one or more industry specifications such as IS-95, IS-856, and IS-2000. Other protocols may be used as well, such as iDEN, TDMA, AMPS, GSM, GPRS, UMTS, EDGE, WiMAX (e.g., IEEE 802.16), LTE, microwave, satellite, MMDS, Wi-Fi (e.g., IEEE 802.11), and others now known or later developed.
Mobile stations typically conduct wireless communications with one or more base transceiver stations (BTSs), each of which are arranged to send communications to and receive communications from mobile stations over the RF air interface. Each BTS is in turn communicatively connected with a network entity known as a base station controller (BSC) (sometimes referred to as a radio network controller (RNC)), which controls one or more BTSs and acts as a conduit between the one or more BTSs and one or more switches or gateways, such as a mobile switching center (MSC) and/or a packet data serving node (PDSN).
To access data networks, such as the Internet or a corporate local-area network (LAN), the mobile stations or “access terminals” and cellular wireless networks or “access networks” may communicate over an air-interface based on the requirements of an Evolution-Data Optimized (EV-DO) standard. In particular, the access terminals and the access network may communicate based on the requirements in Third Generation Partnership Project 2 (3GPP2), “cdma2000 High Rate Packet Data Air Interface Specification”, 3GPP2 C.S00024-A v. 3.0, September 2006 (“the EV-DO Rev. A Standard”), which is incorporated herein by reference for all purposes. Transmissions from the access network to the access terminal occur over a “forward channel” or “forward link” and transmissions from the access terminal to the access network occur over a “reverse channel” or “reverse link”. Transmissions between the access terminal and the access network may be divided into “frames”. Frames in turn may be made up of “slots” (a.k.a. time slots). For example, the EV-DO Rev. A Standard defines a “slot” to be 1.66 . . . ms and a frame to be 16 slots, which equals 26.66 . . . ms. EV-DO Rev. A Standard, §1.11.